If we could get a volunteer to get the SMB/CIFS modules configured . . .
Does not look too hard:
http://www.swerdna.net.au/susesambacifs.html#server
(The Kindle becomes the "linux server")
A much better (greater detail) HowTo:
http://www.brennan.id.au/18-Samba.html
Getting the Kindles to provide a "network share" over either USBnet or Wifi is a big step towards getting rid of the FAT-32 formatted user storage area.